Various medical situations require the continuous or repeated introduction of substances, such as drugs or nutrients to bodily organs or tissues through a hole in a patient's skin, and organ walls (sometimes referred to as "percutaneous introduction"). As shown schematically in FIG. 1, typically, an appropriate tube 100 is introduced from outside the patient's body, through the skin, and into the organ 102 through an incision or surgical opening 104. The opening is referred to as a "gastrostomy." One such condition is a glycogen storage deficiency which requires the delivery of carbohydrates directly into the stomach. Another such condition is one where, for any of various reasons, the patient's normal esophogeal tract is inoperable, and nutrients must be provided directly into the stomach. Patients with tracheotomies often require such gastrostomical feeding, as well as patients with birth anomalies and other malformations.
A typical gastrostomy tube 100 is on the order of twenty five cm (10 inches) long and consists of a flexible tubing section 106, typically five to eight millimeters in diameter, made of a silicone composition that is physiologically inert. The end 130 that is inserted into the patient may have some sort of locking mechanism 108 to prevent its subsequent removal, such as an inflatable balloon that inflates to a size larger than the gastrostomy opening, or what is known as a Malecot tip.
The other, external end 120 of the tube is provided with an enlarged diameter section 110 for connection to the substance source 112. (To simplify discussion, the example of a nutrient supplied to the stomach will be used. However, the prior art and the invention apply to the introduction of other types of liquids, such as medications, testing dies, etc. to be applied to other organs or body cavities, and all are intended to be included in the invention.) The nutrient may be provided by a gravity feed mechanism, a pump, a syringe, or other devices.
Several problems arise in connection with the prior art devices. When nutrient is not being administered, the external end 120 must be closed off or kept gravitationally above the level 116 of liquid in the patient's stomach (or other organ system). Otherwise, if the external end 120 falls below the liquid level 116, liquid will be forced back out from the stomach out the tube and out of the external source end 120. This situation is obviously not desired. It is possible to clamp off the external end 120, so that even if the end falls below the liquid level 116, liquid will not leave the tube 106. A drawback to this solution is that pressure often builds up in the stomach (or other organ), due to the generation of gasses in the stomach, or due to muscular action, resulting from agitation or motion. Clamping off of the tube end 120 prevents relief of the building up pressure, further adding to the irritation, discomfort and pain of the patient.
The problem is particularly acute in connection with young children or infants who must be fed or administered with the gastrostomy tube. Such young individuals are unable, due to lack of maturity, comprehension, patience, etc., to take steps to minimize muscular agitation that increases pressure. Further, the more the pressure builds up, the more irritated or unhappy the young patient becomes, thus crying and fidgeting and tensing up more, causing more pressure, etc. Further, some patients are unable to relieve the buildup of stomach gas pressure through the esophogeal tract, such as by "burping", due to blockages or other problems with the esophogeal tract. Thus, the only path for expulsion of such built-up gasses is through the gastrological tube. The result is a cycle that builds and builds as pressure builds.
A common solution to such a problem is to "vent" the young patients by opening the external end 120, and fixing it above the liquid level 116. Fixing is commonly done by taping the free external end 120 to the patient's body above the liquid level, or to a part of the furniture or other surroundings in which they reside. Such "venting" tends to relieve the pressure for the young patients and calm them down.
A drawback of the venting method is that it results substantially in the demobilization of the patient. Further, if the taping becomes loose, the tube will fall and liquid will escape.
Another problem with known gastrostomy feeding apparatus occurs during feeding or introduction of liquid. Typically, liquid is introduced from a source 112 into the external end 120, and passes into the patient's body, either under the urging of gravity, or pressure established by a pump or syringe. However, even during feeding, the patient, particularly young patients, may become irritated to the extent that the pressure at the internal end 130 of the tube 100 exceeds the pressure at the external end 120, causing back flow or reflux of the contents of the stomach or other organ back out the tube. This presents many problems. It is undesirable for such liquid to mix with the fresh contents of the nutrient in bottle 112. However, if the source is disconnected from the tube 100, the back flowing nutrient will leak out causing a mess. Further, the nutrient is expensive, and attendants often try to save the back flowing nutrient, rather than simply draining it into a sink or other refuse receptacle. Even if the patient does not become agitated, the buildup of pressure from gas or other causes can cause a back flow problem.